Effects of the Inorganic Elemental Composition of Liquid Fertilizers on Rockwool-Cultivated Common Fig (Ficus carica L.)

Abstract

The effects of the inorganic elemental composition of liquid fertilizers on rockwool (mineral wool) - cultivated common fig plant growth as well as fruit yield and quality were investigated. ‘Masui Dauphine’ (synonym of ‘San Piero’) plants were grown in plastic pots containing approximately 13 L rockwool and pruned to a single bearing shoot. The cultivation was performed three times in a closed-type plant cultivation room with artificial light. Two types of liquid fertilizer were applied at two concentrations based on the amount of nitrogen. The liquid fertilizers weakly affected shoot growth (length, number of nodes, and leaf color), whereas the fruiting node rate (number of fruits/number of nodes) was clearly affected by the liquid fertilizer type and concentration. Specifically, the fruiting node rate was high for the liquid fertilizer containing high phosphorus and boron contents and low potassium, magnesium and manganese contents. A comparison of the inorganic elemental composition in the leaves after harvest revealed the fruiting node rate was positively correlated with the phosphorus content, but negatively correlated with the iron content. Therefore, these inorganic elements may be important for increasing the fruit yield of common fig cultivated in rockwool.